mbed-os/targets/TARGET_Silicon_Labs/TARGET_EFM32/trng/trng_api.c

56 lines
1.7 KiB
C

/***************************************************************************//**
* @file trng_api.c
*******************************************************************************
* @section License
* <b>(C) Copyright 2017 Silicon Labs, http://www.silabs.com</b>
*******************************************************************************
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************/
#include "trng_api.h"
#include "sl_trng.h"
#if defined(DEVICE_TRNG)
static bool is_trng_enabled = false;
void trng_init(trng_t *obj)
{
/* Use TRNG0 for all HW entropy collection */
obj->instance = TRNG0;
if(!is_trng_enabled) {
sl_trng_init(obj->instance);
is_trng_enabled = true;
}
}
void trng_free(trng_t *obj)
{
/* Don't turn off the TRNG to avoid clearing its FIFO */
(void) obj;
}
int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_length)
{
int ret = sl_trng_poll(obj->instance,
output,
length,
output_length);
return (ret == 0) ? 0 : -1;
}
#endif /* DEVICE_TRNG */